Woodscrews - Pozidrive Countersunk Twinthread

When it comes to the sizing of woodscrews it is still very common to find measurements in both metric and imperial. The diameter of a wood screw is either given in a gauge (imperial), or in millimeters (metric). With the imperial gauge, a number is used, i.e. 8 gauge. A larger gauge number means a larger diameter. Screw gauge numbers actually correspond to a particular fraction of an inch in imperial measurements.

Woodscrew lengths are also often shown in either metric or imperial sizes, or sometimes both.

A countersunk head is usually used when no part of the fastener head is required to be protruding above the level of the substrate. Countersunk heads can also be recessed and filled over if a hidden fixing is required. Usually abbreviated to CSK.

Pozidrive heads have been designed to ensure that the screwdriver will not slip under torque. This makes them ideal for use with impact drivers and other power tools.

The best way to identify a Pozidrive head is by the diagonal engraved lines between the four points of the cross head.